Abstract
This study of an isolated colony showed that of seven children who escaped the epidemic streptococcus infection none developed rheumatic symptoms; and that of seventeen children who contracted the epidemic streptococcus infection, fourteen developed acute rheumatism and three showed no recognizable rheumatic manifestations. The seven children who failed to contract infection with Streptococcus hemolyticus showed clearly that susceptible individuals may live in dose association with an epidemic of acute rheumatism, develop no rise in antistreptolysin titer and maintain excellent health. The patient with congenital heart disease demonstrated that a non-rheumatic subject may be infected with a highly effective strain of hemolytic streptococcus, and develop a typical antibody response, yet escape all rheumatic manifestations. The two patients who, although infected with the epidemic strain, failed to show any antibody response, also failed to develop rheumatic recrudescences. Environmental, dietary, age and the other factors investigated did not appear to be significant in this outbreak of acute rheumatism. Three factors appeared to determine the development of the fourteen recrudescences: (1) infection with a highly effective agent; (2) the disease pattern, peculiar to each rheumatic subject; (3) the intensity of the immune response of the patient as indicated by the rise in antistreptolysin titer.